Mark's Studio Build Diary - The Construction Phase

Post and discuss acoustic topics, Studio design, construction, and soundproofing here

Postby Scott R. Foster » Sun Jun 13, 2004 12:38 pm

Mark:

T'were it me I'd get those speakers out of the corner and a bit further off the wall.

To start, I'd build a stout shelf on the wall or perhaps a thin shelf which was the width of the desk [sort of like a bookcase the top of which is lower than the desk]. I'd make the top of this new fixture of sufficient strength and depth to hold the PC montiors a couple of inches lower than the desk and set the monitors on it such that their front lower edges rise just above and just overhang the back edge of your desk. The result would be as though you had flat screen units pushed to the back edge of your desk.

As a result, you will not only move your listening postion a bit further off the wall [a distance equal to the depth of the monitors], you also recover a bit of work space on the desk.

Then I'd pull the speakers forward off the back wall and in off the side walls - IOW, towards the back corners of the desk but so as to NOT have the speakers be behind the PC monitors such that the PC montiors are not an impediment to the direct signal from the speaker to your big fat head [or the BFH as we call it in the industry].

My $0.02

Good Luck
SRF
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Postby MarkEdmonds » Sun Jun 13, 2004 6:54 pm

Thanks Scott. I was beginning to think along the same lines.

I've tried the monitors right out from the wall and the sound is marginally better but still wild in some respects. I messed around further and also placed some redundant acoustic tiles on the desk surface which again made a slight improvement.

However, time to get to the real facts and learn EFT so I set everything up and was ready to go but I wasn't getting enough gain on the microphone. Perhaps the EFT mixer will help I thought. It is at times like this that I think I am destined never to get on with EFT. The EFT Mixer repored an error and my sound system went dead. No WDM, DirectSound, MME or whataver sound. Nuendo plays OK so ASIO is alright and the sound card hasn't died.

I tried resetting all the audio defaults blah blah blah, reboot, hard reboot etc but no sound. Next resort: uninstall and reinstall the sound drivers. Clicked on uninstall and the computer completely froze. Tried the same thing via different routes and each time, I get a completely locked solid PC. Bloody great. I can't uninstall and because of the way the Lynx install works, you can't install without a uninstall first. All because I clicked on the EFT Mixer button.

Wasted a good hour on this and still no sound.

What a brilliant way to end the weekend and the last two weeks construction work!!! I've got a room sound which needs serious analysis and a dead Windows sound system. Thank you God!
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Postby Scott R. Foster » Mon Jun 14, 2004 1:02 pm

Go to the recording properties page of the volume control and see if there is an advanced properties button for the mic... if so look and see if there is a 20 dB boost switch for the mic.
SRF
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Postby MarkEdmonds » Mon Jun 14, 2004 6:54 pm

Scott - can you believe how dumb I can get? It was far more basic than that - I didn't have the output from the mixer connected to the sound card!!! Sometimes I shock myself with my stupidity :-((

(Also realised for the first time today that the application is ETF and not EFT)

Mark
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Postby Paul Woodlock » Mon Jun 14, 2004 7:04 pm

MarkEdmonds wrote:.....

(Also realised for the first time today that the application is ETF and not EFT)

Mark



LOL! - Even sillier, is I've been reading your posts with EFT, and I didn't even notice :)


but tehn appraetnly you can raed a jubmle of letetrs qutie eaisly, as lnog as the frist and lsat lteters are corerct. And it wroks :)


Pual
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Postby Bob » Mon Jun 14, 2004 7:35 pm

Thel pweor of the hmuan mnid.

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

amzanig huh?
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Postby Paul Woodlock » Mon Jun 14, 2004 7:47 pm

Bob wrote:
Thel pweor of the hmuan mnid.

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

amzanig huh?


Yep, I culod raed that eisaly!!

:)

This is why the UK National Clothing Chain of Shops called FCUK has so many complaints from sad people.

:)
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Postby MarkEdmonds » Mon Jun 14, 2004 9:24 pm

But it is a valid acronym isn't it? French Connection United Kingdom?

What we need now is someone to come up with a way of using CNUT.

My build diary has gone uphill!
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Postby Paul Woodlock » Tue Jun 15, 2004 12:40 am

MarkEdmonds wrote:But it is a valid acronym isn't it? French Connection United Kingdom?


VERY VERY CLEVER MARKETING INDEED :)

What we need now is someone to come up with a way of using CNUT.


ROFLMAO!!!! :) :) :) :)


Well there could be the underwear company....

"Clothing Needs Under Trousers"

or when Steinberg eventually get their programs bug free....

"Creativity Never Under Threat"

:)

Paul
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Postby MarkEdmonds » Tue Jun 15, 2004 8:25 pm

:-)) Can't match them!




From the point of view of continuity, I've started a new thread with initial ETF results. Here is the link.

http://forum.studiotips.com/viewtopic.php?t=667

I made it a new thread so I didn't have the legacy of not being able to set up ETF correctly (and thus measuring the soundcard output), getting the name of the program wrong and admitting I tried doing measurements without the soundcard inputs being connected. Quite a feat, managing to cock that lot up!!!!
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Postby MarkEdmonds » Fri Jul 02, 2004 10:15 pm

So near and yet so far...

Haven't been very active round here recently so catching up on things...

Last couple of weeks I've been attempting to tune the room prior to starting on the final cosmetic jobs. I've made at least 200 ETF measurements and have the speakers now in their optimum position. When I say "optimum", I of course mean "compromise" because in my type of room, there isn't a perfect solution.

Anyway, during all this testing, I once hit upon a magic spot but as I was between tests, I lost the speaker position and haven't been able to get it back, despite taking accurate measurements. Strange that it should appear to be so sensitive to position when that position is less than one inch in each direction (two inches if you add up error on both monitors).

Having lost the sweet spot, I was getting problems with in-the-ear effects which was making the sound - no bullshit - sometimes painful to listen to. My ETF data was also showing heavy comb filtering which I wasn't expecting given the level of absorption I have.

During many abortive experiments with stacking RW3 bales I then tried stacking them up against the rear wall to increase the depth there and all of a sudden ....... kaboom! the treble soundly became the smoothest and most detailed treble I have ever heard. I'm not joking, it is extraordinary and all those in-the-ear effects went instantly. The rather empty and uneven stereo spread suddenly became smooth all the way across and instrument definition was sharper.

Despite the bass problem (room modes), it now sounds bloody damn good with no fatigue at all. The only problem is the treatment to achieve this looks like this:

Image
Image

Those extra 60cm on the back wall look a bit crazy and completely screw up my plan to put a piano there.

My theory on why this works on the treble is that maybe the wooden frame with regular interval vertical supports was causing reflections to build up at frequency multiples. I don't know if that is bollocks or not but there had to have been a reflection problem for my ears to be hurting in the way they were and the comb filtering shown in the ETF results.

Now, please can anyone suggest a way of getting rid of that 60cm block and placing it elsewhere so I can use the rear wall for a piano and have a more regular looking room? Could it also be possible that the plastic wrapping of the RW3 is having a slight diffusing effect on top of the absorption? Would a fabric covering weaken the effect?

I've still got the room modes to sort out but I can negate them slightly with the mixer controls (nothing major - just a mild scoop at 200Hz).

I'm really excited about this again because if I can get the bass working like the treble then I have a really fantastic sounding room.

Mark
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Postby Dirk Brouns » Sat Jul 03, 2004 6:50 am

Mark,

What about some diffusors on the back wall? Perhaps some poly's, since you thinks it's reflection of higher frequencies that's causing the problem...

Good luck,
Dirk

P.S. Good work!
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Postby Paul Woodlock » Sat Jul 03, 2004 2:23 pm

Greetings Mark


You could try cutting the plastic out of the front of those two front packets of rockwool, and re-test. ( they'll still hold together if you leave a margin around the edge )


Paul
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Postby MarkEdmonds » Sat Jul 03, 2004 3:16 pm

Grettings one and all.

Dirk - I was actually thinking against diffusion because my way of thinking was that the problem was localised reflections. Therefore, get rid of this by absorbing those areas. However, after today's tests, I am now wondering if with good diffusion, the localised reflections (if that is correct) would be spread out and that might fix it.

Paul - yes, been doing that today. See below!...


I think I need to start each entry with a heading to sum up the current state of affairs. Today's is:

Completely Confused!

I thought I would start the day by doing a before and after ETF on the room with the new placement of RW3 blocks. My ears were telling me there was a big difference so it should show up in ETF. My expectation was for reduced combing and flatter high end.

First off, I did a before and after listening test to prove the change was still there. It was but to be honest, not as significant as yesterday.

Then I did the measurements.

Well, the differences were virtually nill. I just don't get that. The combing was almost identical, the waterfalls showed a very slight change and the freq plots were as near as dammit, the same. The only thing I could show to be different was the Schroeder Integration plot.

Completely stumped. What the hell had I changed?

I decided to start experimenting with different heights up the rear wall. I stacked it right to the top and it sounded horrible - way too claustrophobic. I tried different heights in 30cm multiples with the RW3 wrapped and un-wrapped. I felt it was better at 60cm high. I tried different depths on top of this from 10 to 60cm and 120cm high, again wrapped and unwrapped. In this configuration, the RW3 looked like a bench if that helps visualise it. I also tried bundling up the two door corners where there is minimal treatment.

None of this had the right effect. I just couldn't get the treble back to that "from nowhere" sound I had and the differing depths of RW3 pulled the bass in and out a lot.

So, conclusions to draw:

1. I don't know what I am looking for! If I knew what the defining components of the sound characteristics are, I could home in on how to fix them. At the moment, it is blind trial and error.

2. I want to try diffusion but I want to make sure I use good diffusion which means something like Auralex T'Furors. Unfortunately, in the UK, they are really expensive and even buying just four of them for a trial and error test will cost over 200GBP. I can't afford that given it is a gamble. Also, I am not convinced diffusion is the key. At the moment, I am more puzzled by the crazy linear freq plots which look like an continuous earthquake plot on a seismograph!

I'll get back to shuffling the RW3 slabs around. This is only fixing half the equation though as the modes need attention. I've had a taste of how this room can sound when balanced properly. I know it can sound bloody good but I think getting there is an awful long way off as yet.

Mark
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Postby Bob » Sat Jul 03, 2004 3:54 pm

I know you're going for the dead Reflection Free Room.

But I was thinking about the plastic on those bundles reflecting HF, and the importance of getting the right sound from the right place. Perhaps you're getting left/right interchanged or uneven reflections?
Would more HF reflection, from the right places, be a good thing?
Regards
Bob Golds
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Postby Paul Woodlock » Sat Jul 03, 2004 6:56 pm

Personally I think the room is too small for diffusion.

Mark have you tried unwrapping some of that rockwool, and placing it on the floor between your ears ( measurement mic and the speakers?

[just in case:].... You should always measure just ONE speaker at a time. Otherwise, even the smallest path difference between each speaker to mic will show some sort of comb filtering in the highs.

Also don't expect to get the room FLAT.


If you could post some LOG freq plots of current tests it would be nice :)

Paul
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Postby MarkEdmonds » Sat Jul 03, 2004 7:01 pm

Hi Paul - yes, I've been using the slabs unwrapped - but not on the floor between the mic and speakers. Do you think the laminate floor is guilty then? I'll give that a shot although there isn't a clear path between them - desk and keyboard stand in the way.

I'm just off for a while but I'll get some plots up next and also the saved ETF files if people are interested in seeing them.
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Postby MarkEdmonds » Sat Jul 03, 2004 7:03 pm

Hi Bob - I'm convinced there is a reflection problem somewhere but whether diffusion will solve it or not, I don't know.

Incidentally, I've left a telephone message with the UK distributors of Auralex to see if I can loan some T'Fusors and Venuses off them for a couple of weeks. That will be interesting if I can kill off two birds at once.
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Postby MarkEdmonds » Sat Jul 03, 2004 7:10 pm

Paul Woodlock wrote:You should always measure just ONE speaker at a time.


Yes, I never have both on together and the mic is always aimed at the centre of the tweeter (on axis as well).

Also don't expect to get the room FLAT.


Seriously, why not? I know the chances of me getting sub 250Hz flat is laughable but above that, shouldn't it be possible?

Actually, flat or not, what I am aiming for is something that is listenable, accurate and not "hi-fi". At the moment it isn't any of those characteristics.

I don't mind an early tail off on the bass if it needs to be there - as long as I know it is there. Likewise the treble.
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Postby Marlon Wolterink » Sat Jul 03, 2004 8:06 pm

Mark,

did you consider to baffle your speakers?
It did wonders for me, in terms of clarity and definition.
On the picture below you can see how it's done in my homestudio.

The baffling is approx. 8 inches on each side.
Bert Stoltenborg has helped me with this. ( thanx again Bert!)
We started out with using cardboard and that helped alot immediately. Later I made the plywood baffles as you can see on the pictures.

greetings,
Marlon Wolterink.
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